Coal-fired thermal power plants or incineration plants generate high-temperature gas containing a large amount of fly ash (dust), sulfides, nitrides or other contaminants, and if the exhaust flue gas or raw synthesis gas is emitted without processing, the environment of our world will be affected seriously.
According to foregoing mentioned problems, the industrial countries have to determine strict emission standards, and meanwhile, also have to input considerable research and development (R&D) resources to investigate how to remove the harmful pollutants in the gas streams effectively so as to conform to the strict emission standards.
In the issue of removing dust particulates or multi-contaminants from a dirty gas, a granular moving-bed filter is usually utilized to achieve by introducing the contaminated gas to pass through a granular moving-bed filter, which allows filter granules to flow slowly there inside. The collection mechanism of dust particulates of the granular moving bed filter is carried out by sending the contaminated gas to flow passing through a curtain formed by filter granules inside the granular moving-bed filter so as to leave the dust particulates and the multi-contaminants with the filter granules, and finally fleeing the gas with a substantial clean state out of the granular moving bed filter while also allowing the filter granules that are saturated with multi-contaminants to be drained out of the granular moving bed filter. In the art, the more detailed description relating to the granular moving bed filter can be obtained from TW Pat. No. 1337889.
However, since the contaminated gas is, in most case, not uniformly distributed while being fed into and flow inside a granular moving-bed filter, it is common that the majority of the contaminated gas will concentrate to flow through a certain part of the granular moving-bed filter while allowing the other part of the granular moving-bed filter to receive only a minute portion of the contaminated gas, and thereby, the part of the granular moving-bed filter where the majority of the contaminated gas is concentrated will be much more easily to be clogged by dust and contaminants contained in the contaminated gas comparing with the other parts, and eventually the flow of the contaminated gas will be blocked in a way that the filtration efficiency of the granular moving-bed filter will be severely affected.
Therefore, it is in need of an apparatus capable of enabling a turbulent gas flow to become a more uniformly distributed gas flow before the gas flow is allowed to enter a granular moving-bed filter.